Chloroquine-induced lipidosis mimicking Fabry disease

Caseous Calcification of the Mitral Annulus: Calcified Toothpaste of the Heart

ABSTRACT

Caseous calcification of the mitral annulus (CCMA) is a rare variant of mitral annular calcification (MAC) usually described as an antemortem finding. We report a case of sudden cardiac arrest in a 39-year-old male with end-stage renal disease undergoing hemodialysis with a history of Fabry disease by kidney biopsy. Autopsy revealed significant circumferential annular calcification in both mitral and aortic valves with a caseous gross appearance. Histologically, these areas consisted of amorphous basophilic material accompanied by a surrounding granulomatous-appearing infiltrate. Von Kossa staining on non-decalcified tissue revealed strong positive staining, confirming CCMA diagnosis. While identifiable, the atrioventricular node was displaced and distorted by caseous deposits. Toluidine blue staining of myocardium showed osmophilic accumulations, and electron microscopy (EM) showed myeloid/zebra bodies, consistent with Fabry disease. We posit that Fabry disease leads to end-stage kidney disease, altering calcium phosphate metabolism, a proposed mechanism for CCMA. This case highlights the multifactorial nature of sudden cardiac death in decedents with various structural cardiac changes and potential renal-disease-induced electrolyte imbalances. We aim to bring awareness to this rare entity, its potential role in a sudden cardiac death, and to highlight the need to use non-decalcified tissue when staining for calcium to establish the diagnosis.

Double Hit of Hydroxichloroquine and Amiodarone Induced Renal Phospholipidosis in a Patient with Monoclonal Gammopathy and Sclerodermiform Syndrome: A Case Report and Review of the Literature

Phospholipidosis is a rare disorder which consists of an excessive intracellular accumulation of phospholipids and the appearance of zebra bodies or lamellar bodies when looking at them using electron microscopy. This disease is associated with certain genetic diseases or is secondary to drugs or toxins. Drug-induced phospholipidosis encompasses many types of pharmaceuticals, most notably chloroquine, amiodarone or ciprofloxacin. Clinically and histologically, renal involvement can be highly variable, with the diagnosis not being made until the zebra bodies are seen under an electron microscope. These findings may require genetic testing to discount Fabry disease, as its histological findings are indistinguishable. Most of the chemicals responsible are cationic amphiphilic drugs, and several mechanisms have been hypothesized for the formation of zebra bodies and their pathogenic significance. However, the relationship between drug toxicity and phospholipid accumulation, zebra bodies and organ dysfunction remains enigmatic, as do the renal consequences of drug withdrawal. We present, to our knowledge, the first case report of acute renal injury with a monoclonal gammopathy of renal significance, lesions, and sclerodermiform syndrome, with zebra bodies that were associated with the initiation of a hydroxychloroquine and amiodarone treatment, as an example of drug-induced-phospholipidosis.

A narrative review on adverse drug reactions of COVID-19 treatments on the kidney

Studies showed that the respiratory is not the only system affected by coronavirus 2, while cardiovascular, digestive, and nervous systems, as well as essential organs such as the kidneys, can be affected by this virus. In this review, we have studied the epidemiology, clinical, and laboratory findings on COVID-19 infection renal involvement, mortality, physiopathology, remaining renal sequels after recovery, underlying renal disease, and renal injury due to its treatment. Also, protective measures for kidney injury are explained in three levels. Evidence of viral particles and genome in the urine and renal tubular cells and signs of damage such as microangiopathy, hypercoagulopathy, and fibrosis are found in COVID-19 patients. The result of this study showed, in hospitalized COVID-19 patients, that the rate of acute kidney injury (AKI) was up to 46%, with a mortality ranging from 11 to 96%. A considerable proportion of patients with AKI would remain on renal replacement therapy. Proteinuria and hematuria are observed in 87 and 75% patients, and increased Cr and glomerular filtration rate (GFR) <60 ml/min per 1.73 m2 are observed in 29.6 and 35.3% of the patients, respectively. Remedsivir is considered to have adverse effects on GFR. COVID-19 patients need special attention to prevent AKI. Those with underlying chronic kidney disease or AKI need proper and explicit evaluation and treatment to improve their prognosis and decrease mortality, which should not be limited to the hospitalization period.

Hydroxychloroquine-Induced Phospholipidosis - A Forgotten Complication of a Common Drug

Hydroxychloroquine (HCQ) has immunomodulatory and immunosuppressive properties and is used in many rheumatological conditions like systemic lupus erythematosus, rheumatoid arthritis, and Sjogren's syndrome. It is usually a widely used and well-tolerated DMARD (Disease Modifying Anti Rheumatic Drugs). Its most feared toxicities include retinopathy and, rarely, cardiomyopathy. Among its other reported side effects is drug-induced phospholipidosis. Here, we report two cases of HCQ-induced phospholipidosis based on renal biopsy electron microscopy. HCQ-induced phospholipidosis, although uncommon, must be considered as one of the differentials in a patient with persistent proteinuria.

Hydroxychloroquine-Induced Renal Phospholipidosis: Case Report and Review of Differential Diagnoses

Introduction

Renal phospholipidosis describes the accumulation of phospholipids in the lysosomes of kidney cells, in particular podocytes. Originally, this was described primarily in the context of the lysosomal storage disorder Fabry disease. It is now known that a variety of drugs can lead to the accumulation of lysosomal phospholipids.

Case Presentation

We present the case of a 69-year-old female patient suffering chronic kidney disease and systemic lupus erythematosus who underwent a kidney biopsy because of a further increase in serum creatinine levels. There was no evidence of lupus nephritis, but electron microscopy showed zebra bodies as a morphological sign of phospholipidosis. This was most likely drug-induced after 25 years of continuous medication with hydroxychloroquine. A renal biopsy 2 years and 6 months earlier, when the renal function of the patient was distinctively better, showed no signs of renal phospholipidosis. Afterward, medication with hydroxychloroquine was discontinued, and renal function parameters remained stable in the 1-year course.

Conclusion

This case raises the question of how severely impaired renal function affects the risk of hydroxychloroquine-induced renal phospholipidosis and underlines that hydroxychloroquine should be administered with caution in patients with kidney insufficiency. Moreover, we provide a review of the causes of renal phospholipidosis, which have been described in the literature and give an overview of possible differential diagnoses in cases with histologically proven phospholipidosis in renal biopsies.

The Role of α3β1 Integrin Modulation on Fabry Disease Podocyte Injury and Kidney Impairment

Podocyte dysfunction plays a crucial role in renal injury and is identified as a key contributor to proteinuria in Fabry disease (FD), primarily impacting glomerular filtration function (GFF). The α3β1 integrins are important for podocyte adhesion to the glomerular basement membrane, and disturbances in these integrins can lead to podocyte injury. Therefore, this study aimed to assess the effects of chloroquine (CQ) on podocytes, as this drug can be used to obtain an in vitro condition analogous to the FD. Murine podocytes were employed in our experiments. The results revealed a dose-dependent reduction in cell viability. CQ at a sub-lethal concentration (1.0 µg/mL) induced lysosomal accumulation significantly (p < 0.0001). Morphological changes were evident through scanning electron microscopy and immunofluorescence, highlighting alterations in F-actin and nucleus morphology. No significant changes were observed in the gene expression of α3β1 integrins via RT-qPCR. Protein expression of α3 integrin was evaluated with Western Blotting and immunofluorescence, demonstrating its lower detection in podocytes exposed to CQ. Our findings propose a novel in vitro model for exploring secondary Fabry nephropathy, indicating a modulation of α3β1 integrin and morphological alterations in podocytes under the influence of CQ.

Molecular mechanisms in chloroquine-exposed muscle cells elucidated by combined proteomic and microscopic studies

OBJECTIVES

Chloroquine (CQ) is an antimalarial drug with a growing number of applications as recently demonstrated in attempts to treat Covid-19. For decades, it has been well known that skeletal and cardiac muscle cells might display vulnerability against CQ exposure resulting in the clinical manifestation of a CQ-induced myopathy. In line with the known effect of CQ on inhibition of the lysosomal function and thus cellular protein clearance, the build-up of autophagic vacuoles along with protein aggregates is a histological hallmark of the disease. Given that protein targets of the perturbed proteostasis are still not fully discovered, we applied different proteomic and immunological-based studies to improve the current understanding of the biochemical nature of CQ-myopathy.

METHODS

To gain a comprehensive understanding of the molecular pathogenesis of this acquired myopathy and to define proteins targets as well as pathophysiological processes beyond impaired proteolysis, utilising CQ-treated C2C12 cells and muscle biopsies derived from CQ-myopathy patients, we performed different proteomic approaches and Coherent Anti-Stokes Raman Scattering (CARS) microscopy, in addition to immunohistochemical studies.

RESULTS

Our combined studies confirmed an impact of CQ-exposure on proper protein processing/folding and clearance, highlighted changes in the interactome of p62, a known aggregation marker and hereby identified the Rett syndrome protein MeCP2 as being affected. Moreover, our approach revealed-among others-a vulnerability of the extracellular matrix, cytoskeleton and lipid homeostasis.

CONCLUSION

We demonstrated that CQ exposure (secondarily) impacts biological processes beyond lysosomal function and linked a variety of proteins with known roles in the manifestation of other neuromuscular diseases.

Expert opinion on the recognition, diagnosis and management of children and adults with Fabry disease: a multidisciplinary Turkey perspective

This consensus statement by a panel of Fabry experts aimed to identify areas of consensus on conceptual, clinical and therapeutic aspects of Fabry disease (FD) and to provide guidance to healthcare providers on best practice in the management of pediatric and adult patients with FD. This consensus statement indicated the clinical heterogeneity of FD as well as a large number of pathogenic variants in the GLA gene, emphasizing a need for an individualized approach to patient care. The experts reached consensus on the critical role of a high index of suspicion in symptomatic patients and screening of certain at-risk groups to reveal timely and accurate diagnosis of FD along with an increased awareness of the treating physician about the different kinds of pathogenic variants and their clinical implications. The experts emphasized the crucial role of timely recognition of FD with minimal delay from symptom onset to definite diagnosis in better management of FD patients, given the likelihood of changing the disease's natural history, improving the patients' quality of life and the prognosis after enzyme replacement therapy (ERT) administered through a coordinated, multidisciplinary care approach. In this regard, this consensus document is expected to increase awareness among physicians about unique characteristics of FD to assist clinicians in recognizing FD with a well-established clinical suspicion consistent with pathogenic variants and gender-based heterogeneous clinical manifestations of FD and in translating this information into their clinical practice for best practice in the management of patients with FD.

Myeloid bodies is not an uncommon ultrastructural finding

The presence of myeloid bodies (MBs) is classically associated with Fabry disease (FD). However, MBs are also identified in patients without clinical evidence of FD. We attempt to further understand the clinicopathologic significance of incidental MBs in those without FD. Among the 4400 renal biopsies accessioned at the University of Rochester Medical Center from 2010 to 2021, we identified 32 cases showing MBs, 6 of which had FD. Medications were compared between a non-FG and a control-group of randomly selected cases without MBs (non-MBs). Both Fabry-group (FG) and non-Fabry-group (non-FG) were predominantly middle-aged (mean 48 years vs 56, respectively). Non-FG had slight female predominance (1:4), while all in FG were female. The majority of both non-FG and non-MBs cohort were on the same medications reported to cause phospholipidosis except sertraline and hydralazine (p = .04), which were more frequent in non-FG. Ultrastructurally, non-FG tended to show focal MBs in predominantly podocytes, while FG showed more extensive MBs in not only podocytes but also parietal, tubular, endothelial, and myocyte cells (p = .03). In addition, half of FG had another superimposed renal disease including kappa-light chain deposition disease, thin-basement membrane nephropathy, and lithium-related changes. MBs are encountered not only in FD but in other settings including CADs, toxins, and other inheritable diseases. Although secondary causes of MBs typically show less extensive involvement compared to FD, these features overlap. Given the challenges in diagnosing female carriers, the finding of MBs, though not specific to FD, may be the only clue that leads to further work-up and timely diagnosis, underscoring the importance of considering FD among other etiologies in differential diagnosis.

Pathogenesis and Molecular Mechanisms of Anderson-Fabry Disease and Possible New Molecular Addressed Therapeutic Strategies

Anderson-Fabry disease (AFD) is a rare disease with an incidenceof approximately 1:117,000 male births. Lysosomal accumulation of globotriaosylceramide (Gb3) is the element characterizing Fabry disease due to a hereditary deficiency α-galactosidase A (GLA) enzyme. The accumulation of Gb3 causes lysosomal dysfunction that compromises cell signaling pathways. Deposition of sphingolipids occurs in the autonomic nervous system, dorsal root ganglia, kidney epithelial cells, vascular system cells, and myocardial cells, resulting in organ failure. This manuscript will review the molecular pathogenetic pathways involved in Anderson-Fabry disease and in its organ damage. Some studies reported that inhibition of mitochondrial function and energy metabolism plays a significant role in AFD cardiomyopathy and in kidney disease of AFD patients. Furthermore, mitochondrial dysfunction has been reported as linked to the dysregulation of the autophagy-lysosomal pathway which inhibits the mechanistic target of rapamycin kinase (mTOR) mediated control of mitochondrial metabolism in AFD cells. Cerebrovascular complications due to AFD are caused by cerebral micro vessel stenosis. These are caused by wall thickening resulting from the intramural accumulation of glycolipids, luminal occlusion or thrombosis. Other pathogenetic mechanisms involved in organ damage linked to Gb3 accumulation are endocytosis and lysosomal degradation of endothelial calcium-activated intermediate-conductance potassium ion channel 3.1 (KCa3.1) via a clathrin-dependent process. This process represents a crucial event in endothelial dysfunction. Several studies have identified the deacylated form of Gb3, globotriaosylsphingosine (Lyso-Gb3), as the main catabolite that increases in plasma and urine in patients with AFD. The mean concentrations of Gb3 in all organs and plasma of Galactosidase A knockout mice were significantly higher than those of wild-type mice. The distributions of Gb3 isoforms vary from organ to organ. Various Gb3 isoforms were observed mainly in the kidneys, and kidney-specific Gb3 isoforms were hydroxylated. Furthermore, the action of Gb3 on the KCa3.1 channel suggests a possible contribution of this interaction to the Fabry disease process, as this channel is expressed in various cells, including endothelial cells, fibroblasts, smooth muscle cells in proliferation, microglia, and lymphocytes. These molecular pathways could be considered a potential therapeutic target to correct the enzyme in addition to the traditional enzyme replacement therapies (ERT) or drug chaperone therapy.

Does administration of hydroxychloroquine/amiodarone accelerate accumulation of globotriaosylceramide and globotriaosylsphingosine in Fabry mice?

Drug-induced lysosomal storage disease (DILSD) caused by cationic amphiphilic drugs (CADs), which exhibits toxic manifestations and pathological findings mimicking Fabry disease (α-galactosidase A deficiency), has attracted the interests of clinicians and pathologists. Although the affected region is lysosomes in both the diseases, DILSD is characterized by intralysosomal accumulation of phospholipids and Fabry disease that of globotriaosylceramide (Gb3) and globotriaosylsphingosine (Lyso-Gb3). However, it is unknown whether administration of CADs affects the catabolism of Gb3 and Lyso-Gb3 in Fabry disease. In this study, we independently administered hydroxychloroquine/amiodarone to wild-type and Fabry mice and examined the effects of the drugs on the enzyme activity and substrates accumulated in organs and tissues. The results revealed that the administration of the drugs induced accumulation of phosphatidylcholine in both the wild-type and Fabry mice. However, reduction of α-galactosidase A activity in the organs and tissues of the wild-type mice was not found, and the storage of Gb3 and Lyso-Gb3 was not accelerated by these drugs in the Fabry mice. This suggests that hydroxychloroquine/amiodarone do not have any significant impact on the catabolism of Gb3 and Lyso-Gb3 in organs and tissues of both wild-type and Fabry mice.

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Effects of cationic amphiphilic drugs on the catabolism of Gb3/Lyso-Gb3 were examined.

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The drugs induced phospholipidosis in the wild-type and Fabry mice.

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The drugs did not induce reduction of α-galactosidase A activity in the wild-type mice.

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The drugs did not accelerate accumulation of Gb3/Lyso-gb3 in the Fabry mice.

The toxic effects of chloroquine and hydroxychloroquine on skeletal muscle: a systematic review and meta-analysis

The aim of this systematic review was to perform qualitative and quantitative analysis on the toxic effects of chloroquine (CQ) and hydroxychloroquine (HCQ) on skeletal muscles. We designed the study according to PRISMA guidelines. Studies for qualitative and quantitative analyses were selected according to the following inclusion criteria: English language; size of sample (> 5 patients), adult (> age of 18) patients, treated with CQ/HCQ for inflammatory diseases, and presenting and not presenting with toxic effects on skeletal muscles. We collected data published from 1990 to April 2020 using PubMed, Cochrane Library, EMBASE, and SciELO. Risk of bias for observational studies was assessed regarding the ROBIN-I scale. Studies with less than five patients (case reports) were selected for an additional qualitative analysis. We used the software Comprehensive Meta-Analysis at the confidence level of 0.05. We identified 23 studies for qualitative analysis (17 case-reports), and five studies were eligible for quantitative analysis. From case reports, 21 patients presented muscle weakness and confirmatory biopsy for CQ/HCQ induced myopathy. From observational studies, 37 patients out of 1,367 patients from five studies presented muscle weakness related to the use of CQ/HCQ, and 252 patients presented elevated levels of muscle enzymes (aldolase, creatine phosphokinase, and lactate dehydrogenase). Four studies presented data on 34 patients with confirmatory biopsy for drug-induced myopathy. No study presented randomized samples. The chronic use of CQ/HCQ may be a risk for drug-induced myopathy. There is substantiated need for proper randomized trials and controlled prospective studies needed to assess the clinical and subclinical stages of CQ/HCQ -induced muscle myopathy.

Lupus Nephritis and Hydroxychloroquine-Associated Zebra Bodies: Not Just in Fabry Disease

Zebra bodies in kidney biopsy specimens are widely accepted as a specific feature of Fabry disease but they can also be present in a drug-induced mimic of Fabry disease, phospholipidosis. Chloroquine and hydroxychloroquine may both induce zebra body formation and kidney phospholipidosis. However, the frequency and clinical significance of such changes remain unknown. We report 5 serial kidney biopsy cases diagnosed as lupus nephritis during hydroxychloroquine administration. All 5 patients exhibited a few, but varying amounts, of zebra bodies in glomerular intrinsic cells, that is, podocytes, parietal epithelial cells, mesangial cells, and endothelial cells. Most of the zebra bodies detected were subtle, though certainly recognizable; these zebra bodies were much smaller than those observed in Fabry disease. Zebra bodies were not observed in patients with lupus nephritis in the absence of chloroquine or hydroxychloroquine administration. All patients with lupus nephritis who received hydroxychloroquine achieved complete remission during continuous use of hydroxychloroquine, though kidney toxicity of drug-induced phospholipidosis might be masked by immunosuppression. Based on this small series of cases, we speculate that the hydroxychloroquine-associated manifestation of zebra bodies and phospholipidosis in the kidney may be frequent phenomena and may have only a subclinical influence on kidney function, at least in the short term.

Zebra-like bodies in COVID-19: is phospholipidosis evidence of hydroxychloroquine induced acute kidney injury?

COVID-19 (from SARS-CoV-2) is the cause of an ongoing pandemic, with an increasing number of cases and significant mortality worldwide. Clinical trials and extensive studies are being conducted on a large scale for a better understanding of the pathophysiology of this disease and its effect on different organs. Several experimental treatment protocols have been introduced, in which hydroxychloroquine (HCQ) was one of the first drugs used. While patients can develop many side effects of HCQ, studies have documented a rare association of long-term HCQ treatment with zebra-like bodies in the ultrastructural examination of kidney biopsies, a finding typically seen in Fabry's disease, as well as in association with chronic HCQ use, among other drugs. We present a similar finding in the postmortem examination of a male in his early seventies with COVID-19 infection, who received five days of HCQ treatment before stopping the medication due to cardiac and renal toxicity.

Incidental finding of cornea verticillata or lamellar inclusions in kidney biopsy: measurement of lyso-Gb3 in plasma defines between Fabry disease and drug-induced phospholipidosis

INTRODUCTION

Therapy with cationic amphiphilic drugs (Amiodarone or hydroxychloroquine) may result in biochemically and ultrastructurally similar lipid inclusions in many cells also affected by Fabry disease (FD). In addition, it often results in similar clinical manifestations such as cornea verticillata. This may lead to a FD misdiagnosis, especially when a complete medical history is not available to the ophthalmologist confronted with cornea verticillata or to the pathologist examining a kidney biopsy. When enzymatic/genetic test or pathological studies are not conclusive, a specific biomarker may help clarify this dilemma. The plasma globotriaosylsphingosine (lyso-Gb3) assay has high sensitivity and specificity and is elevated above normal levels in FD.

MATERIALS AND METHODS

We measured plasma lyso-Gb3 levels in male patients receiving Amiodarone or hydroxychloroquine and compared it with male patients with classic and late onset variant of FD.

RESULTS

In all Fabry patients (classic and late onset variant) α-GalA activity was deficient in dried blood spot and plasma lyso-Gb3 was above normal levels. Patients on treatment with Amiodarone or hydroxychloroquine had normal values for α-GalA activity and lyso-Gb3 in plasma.

CONCLUSIONS

Even when Amiodarone or hydroxychloroquine may decrease α-GalA activity in vitro or in cell culture, our results showed that in all patients lyso-Gb3 plasma levels remain normal with no evidence of reduction in α-GalA activity, confirming the specificity of this biomarker for the diagnosis of FD.

Myelin bodies in LMX1B-associated nephropathy: potential for misdiagnosis

BACKGROUND

Myelin figures, or zebra bodies, seen on electron microscopy were historically considered pathognomonic of Fabry disease, a rare lysosomal storage disorder caused by alpha-galactosidase A deficiency and associated with X-linked recessive mode of inheritance. More recently, iatrogenic phospholipidosis has emerged as an important alternate cause of myelin figures in the kidney.

METHODS

We report two families with autosomal dominant nephropathy presenting with proteinuria and microscopic hematuria, and the kidney biopsies were notable for the presence of myelin figures and zebra bodies.

RESULTS

Laboratory and genetic work-up for Fabry disease was negative. Genetic testing in both families revealed the same heterozygous missense mutation in LMX1B (C.737G>A, p.Arg246Gln). LMX1B mutations are known to cause nail-patella syndrome, featuring dysplastic nails and patella with or without nephropathy, as well as isolated LMX1B-associated nephropathy in the absence of extrarenal manifestations.

CONCLUSIONS

LMX1B mutation-associated nephropathy should be considered in hereditary cases of proteinuria and/or hematuria, even in the absence of unique glomerular basement membrane changes indicative of nail-patella syndrome. In addition, LMX1B mutation should be included in the differential diagnosis of myelin figures and zebra bodies on kidney biopsy, so as to avoid a misdiagnosis.

Hydroxychloroquine-induced renal phospholipidosis resembling Fabry disease in undifferentiated connective tissue disease: A case report

BACKGROUND

Fabry disease is a kind of lysosomal storage disease resulting from deficient activity of the lysosomal hydrolase alpha-galactosidase A (GLA). A mutation in the GLA gene leads to a loss of activity of alpha-galactosidase A. Some drugs, such as hydroxychloroquine, can cause pathological changes similar to those usually seen in Fabry disease.

CASE SUMMARY

We report the case of a 41-year-old female patient who was diagnosed with undifferentiated connective tissue disease in 2008. Hydroxychloroquine treatment started 2 years ago, and proteinuria and hematuria increased. Renal biopsy demonstrated renal phospholipidosis. Zebra bodies and myelin figures were found by renal electron microscopy and were initially thought to be indicators of Fabry disease. A genetic analysis of the patient and her family members did not reveal mutations in the GLA gene, supporting a diagnosis of hydroxychloroquine-induced renal phospholipidosis.

CONCLUSION

This report reveals one of the adverse effects of hydroxychloroquine. We should pay more attention to hydroxychloroquine-induced renal phospholipidosis.

Insight into the Role of Extracellular Vesicles in Lysosomal Storage Disorders

Extracellular vesicles (EVs) have received increasing attention over the last two decades. Initially, they were considered as just a garbage disposal tool; however, it has progressively become clear that their protein, nucleic acid (namely miRNA and mRNA), and lipid contents have signaling functions. Besides, it has been established that cells release different types of vesicular structures for which characterization is still in its infancy. Many stress conditions, such as hypoxia, senescence, and oncogene activation have been associated with the release of higher levels of EVs. Further, evidence has shown that autophagic–lysosomal pathway abnormalities also affect EV release. In fact, in neurodegenerative diseases characterized by the accumulation of toxic proteins, although it has not become clear to what extent the intracellular storage of undigested materials itself has beneficial/adverse effects, these proteins have also been shown to be released extracellularly via EVs. Lysosomal storage disorders (LSDs) are characterized by accumulation of undigested substrates within the endosomal–lysosomal system, due either to genetic mutations in lysosomal proteins or to treatment with pharmacological agents. Here, we review studies investigating the role of lysosomal and autophagic dysfunction on the release of EVs, with a focus on studies exploring the release of EVs in LSD models of both genetic and pharmacological origin. A better knowledge of EV-releasing pathways activated in lysosomal stress conditions will provide information on the role of EVs in both alleviating intracellular storage of undigested materials and spreading the pathology to the neighboring tissue.

Hydroxychloroquine-induced podocytopathy mimicking Fabry disease

Hydroxychloroquine (HCQ) is largely prescribed as an immunomodulator to prevent systemic diseases flares in patients with systemic lupus erythematous, rheumatoid arthritis, Sjogren's disease. Among reported side effects, HCQ can accumulate in lysosomes and induced phospholipidosis. Here, we report an HCQ-induced podocytopathy mimicking Fabry disease (FD). They share the same histological lesions: cytoplasmic vacuolisation of the podocytes and zebra bodies on light and electronic microscopy. FD has been ruled out by measuring enzymatic activity and genetic test. The persistence of proteinuria after immunological remission of a systemic disease treated with HCQ could suggest this HCQ-induced podocytopathy.

Long-term Outcomes of Kidney Transplantation in Fabry Disease

BACKGROUND

Fabry disease (FD) is a rare X-linked lysosomal storage disorder caused by mutations in the α-galactosidase A gene that obliterate or markedly reduce α-galactosidase A activity. This results in the systemic accumulation of its glycosphingolipid substrates in body fluids and organs, including the kidney. Fabry nephropathy can lead to end-stage renal disease requiring kidney transplantation. Little is known about its long-term outcomes and the overall patient survival after kidney transplantation.

METHODS

Here, we report 17 Fabry patients (15 male and 2 female subjects) who received kidney transplants and their long-term treatment and follow-up at 4 specialized Fabry centers.

RESULTS

The posttransplant follow-up ranged to 25 years, with a median of 11.5 (range, 0.8-25.5] years. Graft survival was similar, and death-censored graft survival was superior to matched controls. Fabry patients died with functioning kidneys, mostly from cardiac causes. In 2 male subjects 14 and 23 years posttransplant, the grafts had a few typical FD lamellar inclusions, presumably originating from invading host macrophages and vascular endothelial cells.

CONCLUSIONS

We conclude that kidney transplantation has an excellent long-term outcome in FD.

A Designer Synbiotic Attenuates Chronic-Binge Ethanol-Induced Gut-Liver Injury in Mice

Gut dysbiosis and altered short-chain fatty acids are associated with ethanol-induced liver injury. SCFA are fermentation byproducts of the gut microbiota known to have many beneficial biological effects. We tested if a designer synbiotic could protect against ethanol-induced gut-liver injury. C57BL/6 female mice were exposed to chronic-binge ethanol feeding consisting of ethanol (5% vol/vol) for 10 days, followed by a single gavage (5 g/kg body weight) 6 h before euthanasia. A group of mice also received oral supplementation daily with a designer synbiotic, and another group received fecal slurry (FS); control animals received saline. Control mice were isocalorically substituted maltose dextran for ethanol over the entire exposure period. Ethanol exposure reduced expression of tight junction proteins in the proximal colon and induced hepatocyte injury and steatosis. Synbiotic supplementation not only mitigated losses in tight junction protein expression, but also prevented ethanol-induced steatosis and hepatocyte injury. Ethanol exposure also increased hepatic inflammation and oxidative stress, which was also attenuated by synbiotic supplementation. Mice receiving FS were not protected from ethanol-induced liver injury or steatosis. Results were associated with luminal SCFA levels and SCFA transporter expression in the proximal colon and liver. These results indicate supplementation with a designer synbiotic is effective in attenuating chronic-binge ethanol-induced gut-liver injury and steatosis in mice, and highlight the beneficial effects of the gut microbial fermentation byproducts.

Effects of concurrent chloroquine and ethanol administration on the rat kidney morphology

Introduction

The use of antimalarial chloroquine in malaria-endemic regions of Africa is rampant and it is not uncommon to find individuals taken the drug concurrent with alcohol. Effects of anti-malarial drug chloroquine (Chq) and ethanol (Et) combination on kidney volume and function using rat model was investigated.

Methods

32 adult male rats were randomly distributed into four groups of 8 rats each. Group C serve as control and received vehicle only, while Q is Chq treated only, E is Et treated and QE is Et and Chq treated. Chq was administered intraperitoneally at 1mg/100g body weight weekly and 6% Et in drinking water provided ad libitum. Urine volume was collected before the treatment began and after the treatment. After eight weeks, all animals were euthanized; kidneys were harvested and fixed in 10% neutral formalin. The fixed left kidneys were scanned with computed tomography and the scan slices were used to estimate 3-dimensional kidney volume on ImageJ.

Results

Total kidney volume was none significantly increased in Q, E and QE treated compared to control groups (p = 0.5150). Also, microscopic analysis showed increased proximal tubule diameter (p = 0.1426) and epithelial hypertrophy (p = 0.2530) and significant urinary space shrinkage (p = 0.00001). The initial urine volume was not significantly different between the control and treated groups (p = 0.9864) however, following treatment urine volume was significantly reduced in QE rats group (p = 0.0029).

Conclusion

The results suggest chloroquine and ethanol combination as potential cause of kidney injury through structural damage and function derangement.

Fabry Nephropathy

Fabry disease is a rare X-linked recessive lysosomal storage disease. Multiple mutations of the GLA gene lead to a deficient or absent activity of the lysosomal enzyme α-galactosidase A, resulting in progressive glycotriaosylceramide accumulation in many organs. Low α-galactosidase A activity and mutations in the GLA gene confirm the diagnosis. Clinical signs are multisystemic, heterogeneous, and progressive. Renal, cardiac, and neurovascular involvements are the main life-threatening complications, highlighting the importance of an early initiation of enzyme replacement therapy improving long-term outcome. Fabry nephropathy lesions are characterized by a cell vacuolization of glomeruli, tubules, interstitium, and arteries and by ultrastructural myelin bodies. The main histologic differential diagnoses are toxicity of lysosomal inhibitors and other renal lipidoses. Renal biopsies are not necessary for diagnosis but have an important role in the evaluation of disease evolution and treatment efficiency, which is a major challenge for improving outcome and quality of life.

N370S-GBA1 mutation causes lysosomal cholesterol accumulation in Parkinson's disease

BACKGROUND

Heterozygous mutations in the GBA1 gene, which encodes the lysosomal enzyme β-glucocerebrosidase-1, increase the risk of developing Parkinson's disease, although the underlying mechanisms remain unclear. The aim of this study was to explore the impact of the N370S-GBA1 mutation on cellular homeostasis and vulnerability in a patient-specific cellular model of PD.

METHODS

We isolated fibroblasts from 4 PD patients carrying the N370S/wild type GBA1 mutation and 6 controls to study the autophagy-lysosome pathway, endoplasmic reticulum stress, and Golgi apparatus structure by Western blot, immunofluorescence, LysoTracker and Filipin stainings, mRNA analysis, and electron microscopy. We evaluated cell vulnerability by apoptosis, reactive oxygen species and mitochondrial membrane potential with flow cytometry.

RESULTS

The N370S mutation produced a significant reduction in β-glucocerebrosidase-1 protein and enzyme activity and β-glucocerebrosidase-1 retention within the endoplasmic reticulum, which interrupted its traffic to the lysosome. This led to endoplasmic reticulum stress activation and triggered unfolded protein response and Golgi apparatus fragmentation. Furthermore, these alterations resulted in autophagosome and p62/SQSTM1 accumulation. This impaired autophagy was a result of dysfunctional lysosomes, indicated by multilamellar body accumulation probably caused by increased cholesterol, enlarged lysosomal mass, and reduced enzyme activity. This phenotype impaired the removal of damaged mitochondria and reactive oxygen species production and enhanced cell death.

CONCLUSIONS

Our results support a connection between the loss of β-glucocerebrosidase-1 function, cholesterol accumulation, and the disruption of cellular homeostasis in GBA1-PD. Our work reveals new insights into the cellular pathways underlying PD pathogenesis, providing evidence that GBA1-PD shares common features with lipid-storage diseases. © 2017 International Parkinson and Movement Disorder Society.

Lysosomal storage diseases

Lysosomes are cytoplasmic organelles that contain a variety of different hydrolases. A genetic deficiency in the enzymatic activity of one of these hydrolases will lead to the accumulation of the material meant for lysosomal degradation. Examples include glycogen in the case of Pompe disease, glycosaminoglycans in the case of the mucopolysaccharidoses, glycoproteins in the cases of the oligosaccharidoses, and sphingolipids in the cases of Niemann-Pick disease types A and B, Gaucher disease, Tay-Sachs disease, Krabbe disease, and metachromatic leukodystrophy. Sometimes, the lysosomal storage can be caused not by the enzymatic deficiency of one of the hydrolases, but by the deficiency of an activator protein, as occurs in the AB variant of GM2 gangliosidosis. Still other times, the accumulated lysosomal material results from failed egress of a small molecule as a consequence of a deficient transporter, as in cystinosis or Salla disease. In the last couple of decades, enzyme replacement therapy has become available for a number of lysosomal storage diseases. Examples include imiglucerase, taliglucerase and velaglucerase for Gaucher disease, laronidase for Hurler disease, idursulfase for Hunter disease, elosulfase for Morquio disease, galsulfase for Maroteaux-Lamy disease, alglucosidase alfa for Pompe disease, and agalsidase alfa and beta for Fabry disease. In addition, substrate reduction therapy has been approved for certain disorders, such as eliglustat for Gaucher disease. The advent of treatment options for some of these disorders has led to newborn screening pilot studies, and ultimately to the addition of Pompe disease and Hurler disease to the Recommended Uniform Screening Panel (RUSP) in 2015 and 2016, respectively.

Ultrastructural deposits appearing as "zebra bodies" in renal biopsy: Fabry disease?- comparative case reports

Background

Fabry Disease (FD) is a genetic disorder caused by alpha-galactosidase A deficiency. Certain drugs, such as hydroxychloroquine, can produce renal deposits that mimic morphological findings seen in FD, characterizing a type of drug-induced renal phospholipidosis.

Case presentation

Case 1: A 28-year-old female patient with systemic lupus erythematosus who had been using hydroxychloroquine for 14 months presented subnephrotic proteinuria. Renal biopsy showed deposits compatible with FD. Neither activity analysis of alpha-galactosidase A nor genetic analysis were available and were not performed. These deposits were not detected in a subsequent renal biopsy three years after withdrawal of the medication, characterizing a possible hydroxychloroquine-induced renal phospholipidosis. Case 2: A 29-year-old male patient presented with acroparesthesia, angiokeratomas, cornea verticillata and subnephrotic proteinuria. Deposits compatible with FD were detected upon renal biopsy. The evaluation of alpha-galactosidase A showed no activity in both blood and leukocytes. Genetic analysis identified an M284 T mutation in exon 6, and such mutation was also found in other family members.

Conclusion

Clinical investigation is necessary in suspected cases of Fabry Disease upon renal biopsy in order to confirm diagnosis. Drug-induced renal phospholipidosis should be considered in differential diagnosis in cases with intracellular osmiophilic, lamellar inclusions in electron microscopy.

Alterations in endo-lysosomal function induce similar hepatic lipid profiles in rodent models of drug-induced phospholipidosis and Sandhoff disease

Drug-induced phospholipidosis (DIPL) is characterized by an increase in the phospholipid content of the cell and the accumulation of drugs and lipids inside the lysosomes of affected tissues, including in the liver. Although of uncertain pathological significance for patients, the condition remains a major impediment for the clinical development of new drugs. Human Sandhoff disease (SD) is caused by inherited defects of the β subunit of lysosomal β-hexosaminidases (Hex) A and B, leading to a large array of symptoms, including neurodegeneration and ultimately death by the age of 4 in its most common form. The substrates of Hex A and B, gangliosides GM2 and GA2, accumulate inside the lysosomes of the CNS and in peripheral organs. Given that both DIPL and SD are associated with lysosomes and lipid metabolism in general, we measured the hepatic lipid profiles in rodent models of these two conditions using untargeted LC/MS to examine potential commonalities. Both model systems shared a number of perturbed lipid pathways, notably those involving metabolism of cholesteryl esters, lysophosphatidylcholines, bis(monoacylglycero)phosphates, and ceramides. We report here profound alterations in lipid metabolism in the SD liver. In addition, DIPL induced a wide range of lipid changes not previously observed in the liver, highlighting similarities with those detected in the model of SD and raising concerns that these lipid changes may be associated with underlying pathology associated with lysosomal storage disorders.

The Application of Paraphenylenediamine Staining for Assessment of Phospholipidosis

Drug-induced phospholipidosis is characterized by intracellular accumulation of phospholipids with lamellar bodies in cells exposed to xenobiotics. Demonstration of the lamellar bodies by transmission electron microscopy (TEM) is the hallmark for a definitive diagnosis of phospholipidosis. However, the preparation of tissue samples for TEM and their ultrastructural evaluation are technically challenging and time consuming. Paraphenylenediamine (PPD) is essentially a fat stain, and the staining mechanism is based upon the osmication of unsaturated lipids. Thus, the application of PPD staining to osmicated tissue samples is considered an optimal way to identify lipids. We evaluated the potential of PPD staining to localize phospholipid accumulations on osmium-fixed semi-thin tissue sections of the lung, kidney, and liver, which were affected with phospholipidosis, under a light microscope. PPD staining revealed the presence of PPD positive dark fine granular material in the cytoplasm for all affected tissues examined, which correlated ultrastructurally with lamellar bodies as well as a light microscopic finding of cytoplasmic vacuolation. The great advantage of PPD is that it can be incorporated into the protocol for standard TEM tissue preparation and significantly improve the efficiency of TEM work. In conclusion, PPD provides a simple, sensitive, and reliable method for visualizing phospholipid accumulation on light microscopy and represents an easy tool to study drug-induced phospholipidosis.

Fabry's disease: an example of cardiorenal syndrome type 5

Cardiorenal syndrome type 5 (CRS-5) includes conditions where there is a simultaneous involvement of the heart and kidney from a systemic disorder. This is a bilateral organ cross talk. Fabry's disease (FD) is a devastating progressive inborn error of metabolism with lysosomal glycosphingolipid deposition in variety of cell types, capillary endothelial cells, renal, cardiac and nerve cells. Basic effect is absent or deficient activity of lysosomal exoglycohydrolase a-galactosidase A. Renal involvement consists of proteinuria, isosthenuria, altered tubular function, presenting in second or third decade leading to azotemia and end-stage renal disease in third to fifth decade mainly due to irreversible changes to glomerular, tubular and vascular structures, especially highlighted by podocytes foot process effacement. Cardiac involvement consists of left ventricular hypertrophy, right ventricular hypertrophy, arrhythmias (sinus node and conduction system impairment), diastolic dysfunction, myocardial ischemia, infarction, transmural replacement fibrosis, congestive heart failure and cardiac death. Management of FD is based on enzymatic replacement therapy and control of renal (with anti-proteinuric agents such as angiotensin-converting enzyme inhibitors-and/or angiotensin II receptor blockers), brain (coated aspirin, clopidogrel and statin to prevent strokes) and heart complications (calcium channel blockers for ischemic cardiomyopathy, warfarin and amiodarone or cardioverter device for arrhythmias).

Neuronal Storage Disease in a Group of Captive Humboldt Penguins (Spheniscus humboldti)

A neuronal storage disease affecting 5 captive Humboldt penguins is described. One bird died after 3 days of lethargy and anorexia. The 4 remaining birds died after a slowly progressing course of disease with signs that included lethargy, weakness, and neurologic dysfunction. Neurologic signs included dysphagia and ataxia. Gross lesions in the first animal to die consisted of hepatosplenomegaly indicative of avian malaria, which was confirmed histologically. The 4 remaining animals were mildly to moderately emaciated. Moderate to marked vacuolation of the neuronal perikarya was observed in Purkinje cells, neurons of the brainstem nuclei, and motorneurons of the spinal cord in all birds. By electron microscopy the vacuoles represented multilayered concentric lamellar structures. These findings were indicative of sphingolipidosis. All animals had been prophylactically treated for avian malaria, aspergillosis, and possible bacterial infections with chloroquine, itraconazole, and enrofloxacin. circumstantial evidence implicates chloroquine therapy as the possible cause of the storage disease.

Familial hypertrophic obstructive cardiomyopathy with the GLA E66Q mutation and zebra body

Background

Fabry disease is caused by mutations in the α-galactosidase A (GLA) gene, which is located in X-chromosome coding for the lysosomal enzyme of GLA. Among many gene mutations, E66Q mutation is under discussion for its pathogenicity because there is no clinical report showing pathological evidence of Fabry disease with E66Q mutation.

Case presentation

A 65-year-old Japanese female was referred to our hospital for chest discomfort on effort. Transthoracic echocardiography showed severe left ventricular (LV) hypertrophy with LV outflow obstruction. Maximum LV outflow pressure gradient was 87 mmHg, and Valsalva maneuver increased the pressure gradient up to 98 mmHg. According to medical interview, one of her younger sister and a nephew died suddenly at age 42 and 36, respectively. Another younger sister also presented LV hypertrophy with outflow obstruction. Maximum LV outflow pressure gradient was 100 mmHg, and the E66Q mutation was detected similar to the case. Endomyocardial biopsy specimens presented vacuolation of cardiomyocytes, in which zebra bodies were detected by electron microscopic examination. Although the enzymatic activity of GLA was within normal range, the c. 196G>C nucleotide change, which lead to the E66Q mutation of GLA gene, was detected. We initially diagnosed her as cardiac Fabry disease based on the findings of zebra body. However, immunostaining showed few deposition of globotriaosylceramide in left ventricular myocardium, and gene mutations in the disease genes for hypertrophic cardiomyopathy (HCM), MYBPC3 and MYH6, were detected. Although the pathogenicity of the E66Q mutation cannot be ruled out, hypertrophic obstructive cardiomyopathy (HOCM) was more reasonable to explain the pathophysiology in the case.

Conclusions

This is the confusable case of HOCM with Fabry disease with the GLA E66Q mutation. We have to take into consideration the possibility that some patients with the E66Q mutation may have similar histological findings of Fabry disease, and should be examed the possibility for harboring gene mutations associated with HCM.

Renal phospholipidosis possibly induced by ranolazine

A 76-year-old male Caucasian patient was treated in our hospital for acutely decompensated heart failure due to restrictive cardiomyopathy. Acute-on-chronic kidney failure developed with serum creatinine rising from 160 to 345 μmol/L (1.8-3.9 mg/dL); therefore, a kidney biopsy was performed. Besides secondary focal-segmental glomerulosclerosis and minimal amyloidosis, histological analysis showed zebra bodies in the cytoplasm of some podocytes, suggesting renal phospholipidosis (PL). Possible causes for this storage disorder encompass Fabry's disease, in rare cases silicosis, and an iatrogenic drug-induced aetiology. The main suspects are cationic amphiphilic drugs, such as amiodarone and chloroquine. The only cationic amphiphilic drug our patient had taken was the anti-anginal ranolazine, a compound not yet associated with PL. The patient had taken ranolazine for diastolic dysfunction over a period of 9 months until 6 weeks before renal biopsy. In the absence of a hereditary disorder, silicosis and well-known pharmaceutical triggers, a causative role of ranolazine seems likely, and this drug should be considered in the differential diagnosis of drug-induced PL.

Hydroxychloroquine-induced phospholipidosis in a case of SLE: the wolf in zebra clothing

A 30 year old lady patient of SLE on steroid and hydroxychloroquine therapy presented with lupus nephritis and later developed cardiac symptoms. Her renal biopsy revealed features of Class III lupus nephritis. Also seen was typical lamellated myelinoid material in the glomerulus. The alpha-galactosidase A activity was normal. The clinical morphological and biochemical findings were consistent with Lupus nephritis showing changes of hydroxychloroquine induced phopholipidosis. Electron microscopy along with careful clinical examination and follow up status was instrumental in the diagnosis of the latter.

Curvilinear bodies in hydroxychloroquine-induced renal phospholipidosis resembling Fabry disease

Inherited and acquired metabolic disorders are responsible for renal intracellular accumulation of phospholipids. Ultrastructural analysis revealing typical myeloid or zebra bodies was previously thought to be exclusive to Fabry disease. However, chloroquine/hydroxychloroquine toxicity can cause similar abnormalities. Recent studies have mentioned curvilinear bodies (CLB) in renal cells in such cases, never described in Fabry nephropathy. We report a 31-year-old patient with systemic lupus erythematosus who was on long-term hydroxychloroquine treatment. The presence of zebra bodies on electron microscopy lead to initial interpretation of Fabry disease, but subsequent genetic analysis did not show a relevant mutation. Further evaluation revealed CLB in renal cells, supporting the diagnosis of hydroxycholoroquine-induced renal phospholipidosis.

A renal variant of Fabry disease: A case with a novel Gal A hemizygote mutation

BACKGROUND

Fabry disease is caused by an X-linked recessive inborn error of glycosphingolipid metabolism with deficient activity of a lysosomal enzyme, alpha-galactosidase A (α-GalA).

CASE PRESENTATION

A 46 year-old man with progressive kidney disease showed on kidney biopsy electron microscopic evidence of Fabry disease. The patient had no systemic manifestations of Fabry disease, despite residual α-GalA activity, therefore genetic testing was done by direct DNA sequencing, demonstrating a new GAL A gene mutation (C174G-exon 3). After three years of enzyme replacement therapy (agalsidase beta) treatment, a second biopsy was done. Although there was demonstrable clearance of intracellular inclusions, remarkable podocyte activation was evident.

CONCLUSIONS

This report represents an unusual renal variant of Fabry disease and provides histologic data on long-term follow up after enzyme replacement therapy.

Comparison of the Diagnostic Accuracy of Di-22:6-Bis(monoacylglycerol)Phosphate and Other Urinary Phospholipids for Drug-Induced Phospholipidosis or Tissue Injury in the Rat

Cationic amphiphilic drugs and aminoglycoside antibiotics can induce phospholipidosis (PLD), an abnormal accumulation of phospholipids in lysosome-derived vesicles, in preclinical studies. The incidence of PLD in patients and its clinical relevance are difficult to assess without noninvasive biomarkers. Di-docosahexaenoyl bis(monoacylglycerol)phosphate (di-22:6-BMP) is a phospholipid that is enriched in lysosomal membranes and a proposed urinary biomarker of drug-induced PLD. The specificity of di-22:6-BMP for PLD was compared to other phospholipid species that can increase in urine with nephrotoxicity. Using liquid chromatography coupled to mass spectrometry, 12 phospholipids were assayed in the urine of rats treated with drugs that induced PLD or caused renal or skeletal muscle injury. In receiver operating curve analyses, urinary di-22:6-BMP was a significantly better predictor of PLD and the least predictive of tissue injury of the phospholipids assayed. The data provide evidence supporting the use of di-22:6-BMP as a urinary biomarker of PLD in rats.

Fabry disease

Fabry disease (FD) is a progressive, X-linked inherited disorder of glycosphingolipid metabolism due to deficient or absent lysosomal α-galactosidase A activity. FD is pan-ethnic and the reported annual incidence of 1 in 100,000 may underestimate the true prevalence of the disease. Classically affected hemizygous males, with no residual α-galactosidase A activity may display all the characteristic neurological (pain), cutaneous (angiokeratoma), renal (proteinuria, kidney failure), cardiovascular (cardiomyopathy, arrhythmia), cochleo-vestibular and cerebrovascular (transient ischemic attacks, strokes) signs of the disease while heterozygous females have symptoms ranging from very mild to severe. Deficient activity of lysosomal α-galactosidase A results in progressive accumulation of globotriaosylceramide within lysosomes, believed to trigger a cascade of cellular events. Demonstration of marked α-galactosidase A deficiency is the definitive method for the diagnosis of hemizygous males. Enzyme analysis may occasionnally help to detect heterozygotes but is often inconclusive due to random X-chromosomal inactivation so that molecular testing (genotyping) of females is mandatory. In childhood, other possible causes of pain such as rheumatoid arthritis and 'growing pains' must be ruled out. In adulthood, multiple sclerosis is sometimes considered. Prenatal diagnosis, available by determination of enzyme activity or DNA testing in chorionic villi or cultured amniotic cells is, for ethical reasons, only considered in male fetuses. Pre-implantation diagnosis is possible. The existence of atypical variants and the availability of a specific therapy singularly complicate genetic counseling. A disease-specific therapeutic option - enzyme replacement therapy using recombinant human α-galactosidase A - has been recently introduced and its long term outcome is currently still being investigated. Conventional management consists of pain relief with analgesic drugs, nephroprotection (angiotensin converting enzyme inhibitors and angiotensin receptors blockers) and antiarrhythmic agents, whereas dialysis or renal transplantation are available for patients experiencing end-stage renal failure. With age, progressive damage to vital organ systems develops and at some point, organs may start to fail in functioning. End-stage renal disease and life-threatening cardiovascular or cerebrovascular complications limit life-expectancy of untreated males and females with reductions of 20 and 10 years, respectively, as compared to the general population. While there is increasing evidence that long-term enzyme therapy can halt disease progression, the importance of adjunctive therapies should be emphasized and the possibility of developing an oral therapy drives research forward into active site specific chaperones.

Bis(monoacylglycero)phosphate, a peculiar phospholipid to control the fate of cholesterol: Implications in pathology

Bis(monoacylglycero)phosphate (BMP) is a structural isomer of phosphatidylglycerol that exhibits an unusual sn1:sn1' stereoconfiguration, based on the position of the phosphate moiety on its two glycerol units. Early works have underlined the high concentration of BMP in the lysosomal compartment, especially during some lysosomal storage disorders and drug-induced phospholipidosis. Despite numerous studies, both biosynthetic and degradative pathways of BMP remained not completely elucidated. More recently, BMP has been localized in the internal membranes of late endosomes where it forms specialized lipid domains. Its involvement in both dynamics and lipid/protein sorting functions of late endosomes has started to be documented, especially in the control of cellular cholesterol distribution. BMP also plays an important role in the late endosomal/lysosomal degradative pathway. Another peculiarity of BMP is to be naturally enriched in docosahexaenoic acid and/or to specifically incorporate this fatty acid compared to other polyunsaturated fatty acids, which may confer specific biophysical and functional properties to this phospholipid. This review summarizes and updates our knowledge on BMP with an emphasis on its possible implication in human health and diseases, especially in relation to cholesterol homeostasis.

Drug-induced Kidney Disease – Pathology and Current Concepts

The kidneys can be damaged by a large number of therapeutic agents. The aim of this article is to discuss the pathological features of drug-induced renal disease as diagnosed by kidney biopsy. The literature is reviewed and cases seen by the authors that have a known drug association are analysed. Mechanisms of injury are varied and all renal structures may be affected. The tubulointerstitial compartment is most frequently involved, but glomerular and vascular lesions are seen in a significant proportion of cases. Key words: Drug, Kidney, Nephrotoxicity, Pathology

Recommendations and guidelines for the diagnosis and treatment of Fabry nephropathy in adults

Progressive loss of kidney function complicates Fabry disease, an X-linked lysosomal storage disorder that arises from deficiency of alpha-galactosidase activity. Heterozygous females with Fabry disease can be as severely affected as hemizygous males, who have the classic form of the disease. Enzyme-replacement therapy with recombinant human alpha-galactosidase clears the glycosphingolipid globotriaosylceramide from kidney cells, and can stabilize renal function in adults with mild to moderate Fabry nephropathy. However, adults with more advanced nephropathy and overt proteinuria do not respond as well. For these patients, antiproteinuric therapy given in conjunction with enzyme-replacement therapy might prevent further decline in kidney function. In this Review, we propose guidelines and recommendations for the diagnosis and management of Fabry nephropathy in adults, based on published data and on the consensus of opinion of participants in the 7(th) International Fabry Nephropathy Roundtable in 2007. These organ-specific guidelines could be easier to implement than general guidelines, provided they are used in the context of an overall multisystem care approach.

Fabry disease: a morphologic study of 11 cases

Fabry disease is a metabolic disorder caused by the genetic deficiency of alpha-galactosidase A. Deposition of glycosphingolipids in podocytes, endothelial cells, and other cell types leads to formation of myelin-like inclusions, which are the hallmark of the disease. In most untreated males, the disorder progresses to end-stage kidney disease. Fabry disease is rare, and no renal biopsy series focusing on pathologic findings has been published in the past 25 years. We retrieved kidney biopsies diagnosed with Fabry disease from our files, and reviewed clinical data as well as the light and electron microscopy. In total, 11 patients were identified: six male subjects aged 17-43 years and five female subjects aged 30-73 years. On average, male patients presented more than 10 years earlier then female patients. A total of 10 patients had proteinuria, two with the nephrotic syndrome. Four male and three female patients had decreased renal function. Light microscopy showed vacuolization of the podocyte cytoplasm and variable glomerular sclerosis. Older patients and males had more advanced glomerular and interstitial sclerosis, but three of the five female patients also had advanced renal disease. Electron microscopy showed the characteristic myelin-like inclusions most prominently in the podocyte cytoplasm. Seven patients also had podocyte foot process effacement. A second type of deposit, unexpected and conspicuous, was identified in three males, and found to be associated with glomerular basement membrane duplications. These deposits were composed of layered membrane-like material, and therefore morphologically distinct from myelin-like inclusions. They probably represent remnants of damaged endothelial cells.